1. Field of the Invention:
This invention relates to a new process for the production of 2-benzyl fatty acids.
2. Statement of Related Art:
Modified fatty acids, more especially saturated fatty acids with a branch in the otherwise linear fatty chain, show certain advantages in the terms of practical application over the natural, linear fatty acids. These advantages are attributable, inter alia, to the fact that, through the introduction of a branch into the molecule, molecular weight and boiling point are increased while, at the same time, volatility and melting point are reduced. These advantages are shown not only by the fatty acids themselves, but also by soaps, esters, amides, nitriles, amines, and derivatives thereof obtainable from the fatty acids. Accordingly, there has been no shortage of attempts to introduce substituents into the fatty acid molecule.
Attempts have also been made to introduce benzyl groups into the .alpha.-position (2-position) of fatty acids. V. H. Wallingford et al. (in J. Am. Chem. Soc. 64 (1942), pgs. 580 to 582) attempted to prepare .alpha.-substituted fatty acids, including 2-benzylstearic acid, by alkylation of malonic esters, hydrolysis, and decarboxylation. This process is too complicated for the commercial production of 2-benzyl fatty acids.
H. L. Wehrmeister (in J. Org. Chem. 27 (1962), pgs. 4418 to 4420) described a process for the production of short-chain 2-benzylidenealkane acids in which 2-alkyl-4,4-dimethyl-2-oxazolines are condensed with benzaldehyde and the 2-(1-benzylidene)-alkyl-4,4-dimethyl-2-oxazoline obtained is converted by hydrolysis into the 2-benzylidenealkane acid. This process can only be applied to 2-fatty alky-4,4-dimethyl-2-oxazolines with very poor yields of less than 40%, if at all, using the catalysts described in this publication for the condensation with the benzaldehyde.